JPS6158141A - Electron gun of picture display device - Google Patents

Abstract

PURPOSE:To make less deterioration in emission even in case electron beams are accelerated with a high voltage by forming a rear electrode and a focusing electrode arranged opposed to a plurality of a thermal cathode type line cathode with a glass plate on which indium oxide is vacuum deposited. CONSTITUTION:In case an electron gun to be used for a picture display device is composed of a plurality of thermal cathode type line cathode 10, a rear electrode 9 which accelerates and controls the hot electrons emitted from such cathode toward the anode and a vertical focusing electrode 11 which pulls the hot electrons toward the anode, the rear electrode 9 and vertical focusing electrode 11 are formed by glass plate having the surface, opposed to the cathode 10, where indium oxide is vacuum deposited. Therefore, even when the hot electrons emitted from the line cathode 10 collide with the surface of rear electrode 9 and vertical focusing electrode 11, oxygen gas or chloride gas is not generated. Accordingly, deterioration in emission of cathode 10 can be prevented and long operation life of picture display device can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an image display device in the field of video equipment.゛Structure of the conventional example and its problems In the conventional fluorescent display tube, as shown in FIG.
It is sealed. Inside this vacuum container, a hot cathode type wire cathode 4 is placed opposite the double external oil pump 7, h curved mark + sword 4, and the upper glass plate 1. A back electrode 6 is formed by vapor-depositing indium oxide on the back surface of the electrode, and a grid electrode 7 is formed by etching a thin metal plate such as 426 alloy. The thermoelectrons emitted from the cathode 4 are transferred to the back electrode 6 and the grid electrode 7.
is focused, accelerated and controlled by the anode 8.
is excited to cause the phosphor to emit light, thereby displaying characters such as the shape of the letter φ. However, in the above configuration, since the voltage for accelerating the thermoelectrons emitted from the cathode 4 is extremely low, such as several tens of degrees, even if the grid electrode 7 is bombarded with electrons, the emitted gas deteriorates the emission of the cathode 4. However, image display devices that accelerate electron beams at a high voltage of several tens of kilovolts have the drawback of deterioration of cathode emission and shortened lifespan.

OBJECTS OF THE INVENTION The present invention eliminates the above-mentioned conventional drawbacks and provides an electron gun that prevents deterioration of the emission of an image display device having a plurality of hot cathode type cathodes.

Structure of the Invention The present invention provides a plurality of hot cathode type Kant tree electrodes that face each other,
An electron gun including a back electrode that pushes and controls thermoelectrons emitted from the cathode toward the anode and a focusing electrode that pulls them out toward the anode from a glass plate on which indium oxide is vapor-deposited on the surface facing the cathode, Even if the electron beam is accelerated at a high voltage of several tens of kilovolts, there is no emission deterioration, which is extremely advantageous in terms of the life of the image display device.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. FIG. 2 illustrates an image display device used in the present invention. The image display device divides the screen on the screen into a plurality of sections in the vertical direction, deflects an electron beam in the vertical direction for each section to display a plurality of lines, and further divides the screen into a plurality of sections in the horizontal direction. In each section, phosphors such as RlG and B are made to emit light sequentially, and the amount of electron beam irradiation to the phosphors such as R, G, and E is controlled by color video signals. and displays the television image as a whole. In FIG. 2, the back electrodes 9. Line cathode 10° vertical focusing electrode 11.11' as electron beam source
, vertical deflection electrode 12. Electron beam flow control electrode 13. Horizontal focusing electrode 14. Horizontal deflection electrode 16. Horizontal focusing electrode 13'
, electron beam accelerating electrode 16. An anode 17 and glass containers 18 and 19 are arranged, and the components are housed in the glass container and evacuated. In the configuration of the image display device described above, the electron gun includes a back electrode 9.degree. and a line cathode 10.degree. as an electron beam source. vertical focusing electrode 11.11',
Vertical deflection electrode 12. Electron beam flow control electrode 13. Horizontal focusing electrode 14. horizontal deflection electrode 16° horizontal focusing electrode 13',
Although a structure such as the electron beam accelerating electrode 16 is used, the vertical focusing electrode 11 is directly subjected to electron bombardment by thermionic electrons emitted from the line cathode 1o, so its surface temperature is extremely high. Oxygen gas and the like are mainly generated from the surface of the vertical focusing electrode 11, causing deterioration of the emitter y of the linear cathode 1o. Therefore, the vertical focusing electrode 11 has four
Etched metal sheets such as No. 26 alloy are not preferred, and wet platings of noble metals such as gold and silver are also not preferred. The specific configuration will be explained using FIG. 3. The back electrode 9 and the vertical focusing electrode 11 facing the linear cathode 1Q as an electron beam source are made of glass plates, and indium oxide is vapor-deposited onto the surface of the glass plate facing the linear cathode 10 to form an electron gun. constitutes part of. In the electron gun having the above configuration, even if the surface of the vertical focusing electrode 11 is bombarded with electrons by thermionic electrons emitted from the line cathode 10, oxygen gas will significantly deteriorate the cathode emission since it is made of a glass plate. Almost no chloride gas is generated.

Therefore, there is no variation among the plurality of cathodes, and each cathode can have a sufficient amount of emission, and may be made of indium vapor deposited.

Effects of the Invention As described above, in the present invention, since the back electrode and the vertical focusing electrode that face the line cathode are formed by vapor depositing indium oxide on the glass plate surface, the influence of electron impact by thermionic electrons emitted from the line cathode is reduced. This greatly reduces the brightness and ensures sufficient brightness for an image display device.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of a conventional fluorescent display tube, FIG. 2 is an exploded perspective view showing the structure of the image display device of the present invention, and FIG.
The figure is a sectional view showing the configuration of an electron gun in an embodiment of the present invention. 6... Indium oxide evaporation surface, completed...
Line cathode, 9... Back electrode, 11...
・Vertical focusing electrode.

Claims (1)

[Claims] An electrode facing a plurality of hot cathode type cathodes, a back electrode for pushing and controlling thermoelectrons emitted from the cathodes toward the anode, a focusing electrode for drawing them out toward the anode, and an electrode for indium oxide onto the surface facing the cathodes. An electron gun for an image display device consisting of a vapor-deposited glass plate.